68640577 has 4 divisors (see below), whose sum is σ = 72678276. Its totient is φ = 64602880.

The previous prime is 68640571. The next prime is 68640581. The reversal of 68640577 is 77504686.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 63936016 + 4704561 = 7996^2 + 2169^2 .

It is a cyclic number.

It is not a de Polignac number, because 68640577 - 2²³ = 60251969 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (68640571) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2018824 + ... + 2018857.

It is an arithmetic number, because the mean of its divisors is an integer number (18169569).

Almost surely, 2^68640577 is an apocalyptic number.

It is an amenable number.

68640577 is a deficient number, since it is larger than the sum of its proper divisors (4037699).

68640577 is a wasteful number, since it uses less digits than its factorization.

68640577 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4037698.

The product of its (nonzero) digits is 282240, while the sum is 43.

The square root of 68640577 is about 8284.9608930882. The cubic root of 68640577 is about 409.4431802763.

The spelling of 68640577 in words is "sixty-eight million, six hundred forty thousand, five hundred seventy-seven".